Abstract: By using ASE 350 (Accelerated Solvent Extraction) Shenhua long flame coal was extracted with mixed solvent of carbon disulfide/N-methyl pyrrolidone (CS2/NMP) under high temperature and high pressure, and the extraction rate was about 25%. The extracted residue was degraded by ruthenium ion catalytic oxidation (RICO), then the products were examined with IC and GC/MS, which depends on thermal auxiliary-methyl esterification of tetramethyl ammonium hydroxide (TMAH, 25% methanol solution). The results show that the macromolecular structure of Shenhua coal contains alkyl side chains at a length of C2~28 and alkyl bridge between aromatic rings at a length of C2~22. The aromatic condensation level is relatively low (most are conjugated structure of 2~4 benzene rings). And there are many ether linked aromatic structures, oxygen groups like hydroxyl (-OH), carbonyl (C=O), methoxy (-OCH3), and heteroatom compounds with sulfur and nitrogen.
Abstract: The catalytic deoxygenating experiment of oxygen-bearing coal mine methane (CMM) was carried out in a bench-scale fluidized bed reactor with the spherical Cu-based catalyst. The effects of the bed temperature, the particle size and the space velocity were investigated on the oxygen removal efficiency and CO2 selectivity. The raising bed temperature could promote the O2 conversion due to the high activity of the catalyst. The O2 conversion could reach more than 95% when the temperature was above 450 ℃. The smaller particle size was beneficial to the CO2 selectivity of the catalyst because of the decreasing inner diffusion resistance. The lower space velocity also could improve the O2 removal efficiency when the bed temperature was below 450 ℃ although the improvement almost disappears above 450 ℃ due to the increasing catalytic combustion rate. Additionally, by adjusting the CH4/Air ratio, the catalytic deoxygenation adaptability of the fluidized bed reactor and the catalyst was evaluated for the variable oxygen content in CMM. The results indicate that the process has a perfect oxygen removal performance with the O2 concentration less than 0.2% and the CO2 selectivity more than 98% for the O2 content from 5% to 15% in the simulated CMM.
Abstract: This work studies the amount of gaseous and particle emissions and deposits on heat exchanger surfaces in a boiler fired with commercially available pellets and with pellets primed with magnesium oxide and magnesium hydroxide. The combustion experiments were performed on a residential boiler of 20 kW. Substrates placed in the heat exchanger was analysed with SEM-EDX-mapping to evaluate the chemical composition of the deposits. The results show that particle emissions (PM 2.5) using the additives increased by about 50% and the mass of the deposits in the flue gas heat exchanger (excluding loose fly ash) increased by about 25% compared to the combustion of pellets without additives. The amount of additives was found to be eight times higher than the amount of the main alkali metals potassium (K) and sodium (Na) which leads to the assumption that the additives were overdosed and therefore caused the problems reported. The SEM analysis of the substrates placed in the flue gas heat exchanger indicate that the deposits of sodium (Na), potassium (K), chlorine (Cl) and sulphur (S) decrease using the additives. If this was due to the expected chemical reactions or due to the loose fly ash covering the substrates after the test, could not be determined in this study.
Abstract: The contents of rare earth elements (REEs) in high sulfur coal of Late Permian from Chenxi coalfield, with the organic sulfur content of 7.75%, have been analyzed by HR-ICP-MS. The ΣREE varies from 38.84 to 305.85 μg/g, with the weighted average of 104.57 μg/g which is higher than that of the world coal and similar to that of Chinese coal. The negative anomalies of Ce and Eu in Chenxi coal, with the δCe from 0.74 to 0.84 and the δEu from 0.55 to 0.69, indicate the influence by marine and by terrigenous materials, respectively. The two-stage change of REE content and distribution patterns in the profile suggested the fluctuations in coal-forming environment, with the terrigenous influence decreasing and the marine impact increasing from the floor to the roof of coalseam. This results in the significant difference of the proportion of organic and pyrite sulfur. The pyritic sulfur and the ΣREE in Chenxi coal present a good positive correlation (n=11, r=0.95), which indicates the common source and similar enrichment conditions involving both terrigenous material and marine influence. The distribution pattern of the REEs, the correlation between the ΣREE and ash yield, Si, Al illustrate that the REEs mainly derive from terrigenous materials. The narrow range of δCe and δEu in the profile can be explained by the seawater rebuilding of the rare earth elements in the coal.
Abstract: The fast pyrolysis of Huolinhe lignite under CO atmosphere was carried out in a fixed bed reactor. The distribution characteristics of gases, influence of CO on pyrolysis behaviors were investigated by comparative analyses of FT-IR spectra, element content and surface structure property of the char. The results show that the CO participates in the pyrolysis process and changes the pyrolysis behavior. Below 600 ℃, the polarity of CO, which brings out by the lone pair electrons existed in CO molecule, can help to crack the aromatic ring, side chain, ether linkages and aliphatic chain in the char, resulting in the increase in smaller molecular fragments and free radicals. These free radicals can stabilize the fragments produced during pyrolysis, which contributes to the generation of more volatile including H2, CH4, CO and CO2, as well as less char with higher specific surface area and pore volume. Above 700 ℃, the carbon deposition produced by the increasing CO disproportionation reaction can partially cover the surface of the char and block its pore, leading to the decrease in surface area and pore volume of the char as well as inhibiting the diffusion of CO in the pore structure. This effect suppresses the contact and reaction between CO and organic macromolecules of coal, resulting in the decreases in the yield of H2, CH4 and CO as well as the increase in the yield of CO2 due to CO disproportionation reaction.
Abstract: The steam gasification of XLT, FG and JC coal chars was studied by isothermal thermogravimetric analysis. The relationship between reaction rate and carbon conversion of three coal chars was simulated by shrinking core model(SCM), traditional model(TM) and random pore model(RPM). The results show that TM is the best one overall for three coals. SCM and RPM are not suitable to describe the gasification process of low-rank XLT coal char, though they have satisfied simulation results to the other two coal chars with higher coal rank. The kinetic parameters were calculated by three models, and the reason for their differences was analyzed. Based on the sensitivity analysis method, the error of the prediction with the change of parameters was studied. It is shown that the apparent reaction rate k is a sensitive parameter, and the reaction order n in the TM and the structural parameter ψ in the RPM are less sensitive parameters.
Abstract: Coal bio-oil slurries (CBS) with different coal concentrations were prepared by mixing different type of coal and bio-oil. The apparent viscosity, rheological properties, maximum solid concentration and static stability of the prepared CBS were examined. The result shows that CBS are non-Newtonian fluid with a certain yield stress, and the rheological behavior of CBS can be described by the Bingham plastic fluid model. Both the apparent viscosity and the yield stress of CBS increase with increasing of solid concentrations. The apparent viscosity decreases with increasing of shear rates. The solid concentration of stable CBS prepared by Yangquan anthracite can reach as high as 42% without any additives, followed by bituminous coal and lignite. The flocculation network structure formed by coal particles in the bio-oil can keep good static stability of CBS for 4.0~5.0 days without formation of soft sediment, and for months without hard sediment.
Abstract: Catalytic hydroprocessing of the bio-oil obtained through fast pyrolysis of Chlorella was carried out in a bench-scale continuous-flow fixed-bed reactor equipped with a Ni-Co-Pd/γ-Al2O3 catalyst. The effects of the hydrogenation temperature and the H/oil molar ratio on the moisture content, calorific value, viscosity and cetane number of the refined bio-oils were investigated at the pressure of 2×106 Pa, It was shown that the yield of the refined oil reached 86.1%, and the calorific value and cetane number were increased by 17.94% and 71.2% respectively, while the viscosity was decreased by 66.32% at the temperature of 300 ℃, the pressure of 2×106 Pa and the H/oil mol ratio of 120. The elemental analysis and GC-MS analysis results of the bio-oil before and after hydrogenation show that the H/C mol ratio was increased from 1.55 to 1.97, while the oxygen, nitrogen and sulfur contents were significantly decreased. The deoxidation degree reached 80.46%. The amounts of organic acids, esters, ketones and aldehyde in the refined oils were obviously decreased, while those of alcohols and alkanes were markedly increased.
Abstract: The transformation of nitrogen-containing compounds of Liaohe Atmospheric Residue (LHAR) during slurry-bed hydrocracking was investigated using Fourier transform infrared spectroscopy (FT-IR) and gas chromatography-mass spectrometry (GC-MS). It was turned out that the major basic nitrogen containing compounds were quinoline in light VGO (350~400 ℃), while some part of pyridine and acridine existed as well. C1~5 carbazole and indole were dominating non-basic nitrogen containing compounds. For heavy VGO (400~450 ℃), the major nitrogen containing compounds were acridine and pyridine. After hydrogenation, the major basic nitrogen containing compounds of the light VGO became C1~7 quinoline, benzoquinoline, and C1~2 acridine, while the major non-basic nitrogen compounds were C2, C3 and C7 indole. For the heavy VGO, the major nitrogen containing compounds had become acridine and carbazole. The content of quinoline before and after the hydrogenation reaction in the atmospheric residue fraction decreased with the elevation of boiling point. In addition, after hydrogenation the concentration of quinoline in LHAR had become higher. During the slurry bed hydrocracking reaction, the nitrogen-containing heterocyclic compounds were reduced and part of the non-basic nitrogen containing compounds was converted to basic nitrogen containing compounds.
Abstract: The effects of the sequence of the combined steaming and alkali treatments of ZSM-5 zeolite on its acidic properties and pore structure were investigated and compared with those of individual steaming treatment or alkali treatment. The results showed that the alkali treatment after steaming has triple effects on the resultant ZSM-5 zeolite, i.e. desilication, realumination and removal of extra-framework aluminum; whereas the steaming after alkali treatment has binary effects, i.e. dealumination and stabilization. Compared with the alkali treatment after steaming, the steaming after alkali treatment is more effective in adjusting the zeolite acidic properties and creating mesopores. The catalyst derived from ZSM-5 zeolite modified via the combined alkali treatment and steaming exhibits moderate isomerization activity, higher aromatization activity and superior stability in the hydro-upgrading of fluid catalytic cracking gasoline.
Abstract: Microporous EU-1/ZSM-5 composite zeolites containing iron were synthesized using preset crystal seed method. The as-synthesized Fe-EU-1/ZSM-5 samples were characterized by a serious of techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric-derivative thermogravimetric (TG-DTG), N2 adsorption/desorption, UV-visible diffuse reflectance spectroscopy (UV-Vis DRS) and X-ray absorption fine structure (XAFS). The results show that the composite zeolite is found consisting characteristic diffraction peaks for two kinds of zeolite structure: EU-1 and ZSM-5. The composite zeolite is a kind of molecular dispersion material with two crystal phases interaction and its micropore size is larger than Fe-EU-1 zeolite. With increasing the mass fraction of Fe in the original sol-gel, the characteristic diffraction peaks of composite zeolites in the 23.09° and 23.94° gradually migrate to lower angle direction. UV-vis spectrum shows that there is a broad absorption band at about 220~245 nm. The XAFS results show that the week pre-edge absorption peak for 1s→3d gradually strengthen, at the same time the absorption peak for 1s→4p in the top of absorption edge has tapper. The optimized synthesis conditions for the microporous EU-1/ZSM-5 composite zeolites containing iron are as follows: 0.075%~0.15% of the mass fraction of Fe in the original sol-gel, 15.0%~21.0% of the mass fraction of ZSM-5 zeolite in the original sol-gel and 50~60 of SiO2/Al2O3 mol ratio of ZSM-5 zeolite.
Abstract: Removal of benzothiophenic compounds from fuels plays a key role in deep desulfurization. The adsorptive performance of benzothiophene with typical Metal-Organic Frameworks material MOF-5 was investigated using batch experiments. Results showed that the adsorption kinetics data of benzaothiophene onto MOF-5 from model fuel could be well described by a pseudo-second-order model. The adsorption equilibrium data of benzaothiophene onto MOF-5 fitted well to the Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherm models (Freundlich>D-R>Langmuir). Thermodynamic parameters showed that the adsorption of benzaothiophene onto MOF-5 was spontaneous and endothermic in nature.
Abstract: Phenolic weak acid cation exchange resin was used as carbon precursor to prepare spherical activated carbon supported copper catalyst by ion exchange, carbonization and activation with CO2. The catalyst was characterized by SEM, XRD, AAS and BET. The adsorptive capacities for different sulfur-containing compounds were evaluated by dynamic adsorption experiments and the competitive effects of toluene and cyclohexene were investigated. The mechanism of adsorptive desulfurization was primarily studied as well. The results showed that metals in the spherical activated carbon existed in elemental form and improved the adsorption performance through direct coordination with sulfur atoms. The saturation capacities for thiophene(T), 3-methylthiophene(MT), 2,5-dimethylthiophene(DMT) and benzothiophene(BT) were 0.938, 1.230, 1.581 and 3.744 mg/g, respectively. The adsorptive selectivity increased in the order of T
Abstract: Ce-Co-La-O composite oxide support was prepared by a modified coprecipitation method and the Cu-based catalyst (Cu/Ce-Co-La-O) was then obtained through incipient impregnation; the performance of the Cu/Ce-Co-La-O catalyst in the selective reduction of NO with propylene in excess oxygen was investigated and the relationship between the catalyst structure and performance was explored by means of surface area measurement, X-ray diffraction (XRD), temperature-programmed reduction (H2-TPR), pyridine absorption infrared spectrum (Py-IR), thermal gravimetric analysis (TG) and scanning electron microscope (SEM). The results indicated that Co promoter can increase the amount of Brnsted acidic sites of the Cu-based catalyst and enhance its reducibility. La promoter can further increase the amount of Brnsted acidic sites and the catalyst thermal stability. Meanwhile, Ce-Co-La-O may form a sosoloid and have a synergistic effect on the catalytic performance of Cu/Ce-Co-La-O. Consequently, the Cu/Ce-Co-La-O catalyst exhibits excellent low-temperature activity and thermal stability in the selective reduction of NO; the conversion of NO reaches a maximum of 81.6% at 250 ℃ and is still 52.5% even at 600 ℃.
Abstract: Biomass chars were prepared under different pyrolysis temperatures, pyrolysis rates (rapid and slow pyrolysis) and steam activation temperatures from wheat straw and rice husk; their surface area and pore structure parameters were measured by nitrogen sorption at 77 K. The effects of pyrolysis temperature, pyrolysis rate, steam activation temperature as well as the concentration of SO2 and NO in a simulated flue gas on the adsorption characteristics of SO2 and NO over the biomass chars were carried out in a fixed-bed adsorber. The results indicated that the steam activation can significantly increase the surface area, micropore volume and total pore volume of biomass chars, while decrease their average pore sizes; as a result, the breakthrough time and adsorption capacities of SO2 and NO over the activated biomass chars are increased. Moreover, rapid pyrolysis gives the biomass chars better adsorption characteristics than slow pyrolysis. A pyrolysis temperature of 873 K is superior to 673 and 1 073 K to get biomass chars of high adsorption performance for SO2 and NO. Similarly, there also exists an optimum steam activation temperature between 973 and 1 173 K to prepare activated biomass chars of high adsorption performance. The breakthrough time increases but the adsorption capacities of SO2 and NO decrease with the decrease of the concentration of SO2 and NO in the simulated flue gas. The wheat straw char prepared under the conditions of rapid pyrolysis, pyrolysis temperature of 873 K, and steam activation temperature of 1 073 K performs best for the adsorption of SO2 and NO; over it, the adsorption capacities of SO2 and NO reach 109.02 and 21.77 mg/g, respectively.
Abstract: The influence of calcium-based particles on the selective non-catalytic reduction (SNCR) process was investigated in a drop tube furnace reactor; the tests under different temperatures (600~1 100 ℃), normalized stoichiometric ratio (NSR) of NH3/NO (0.5~2.0) and O2 concentrations (0.5%~5.0%), with ammonia and urea as reducing agents, were considered. The results showed that the raw material, CaCO3 and CaO have inhibitive effect on the SNCR performance; the extent of this effect is significant at low temperature but attenuates with the increase of temperature. Raw material exhibits the strongest inhibitive effect on the SNCR at low temperature because of the catalytic activity of impurity in the raw materials, while CaO has the strongest effect at high temperature. The efficiency of SNCR is increased by increasing NSR, while the effect of calcium-based particles on SNCR remains unchanged. The optimal O2 concentrations for NOx removal is 1% with raw material and 2% with CaCO3 and CaO. The SNCR performance in the presence of calcium-based particles is characterized by the competition of denitration reactions between gaseous de-NOx and the particle-catalyzed oxidation of reductant.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
